Dual-Coil Wireless Power Transfer Layout for Leakage Field Reduction
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in reducing leakage magnetic fields while maintaining power transmission efficiency and avoiding increased physical sizes of coils, leading to interference and reduced coupling coefficients.
Innovation Solution
A wireless power transfer system with power transmitter and receiver coils configured as pairs of coils wound in a horizontal plane with opposite magnetic fields, connected at outside diameter sides, and bent for symmetry, integrated with cores to reduce leakage magnetic fields and maintain efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the distances between coils of a pair of coils included in each of the power transmitter coil and the power receiver coil are configured to be longer than the distance between the power transmitter coil and the power receiver coil, then the leakage magnetic field is reduced, but the physical sizes of the power transmitter coil and the power receiver coil are increased
Solution Approach 1:
The patent applies asymmetry by configuring the pair of coils with different spacing relationships: the distance between the two coils of the pair is made longer than the distance between the power transmitter coil and power receiver coil. This asymmetric arrangement allows the magnetic fluxes to be oppositely oriented and cancel each other more effectively, reducing the leakage magnetic field without requiring symmetric expansion of the entire coil structure.
Solution Approach 2:
The patent utilizes spatial arrangement in multiple dimensions by positioning the pair of coils such that their winding axis directions intersect with the direction connecting the power transmitter and receiver coils. This three-dimensional configuration enables effective leakage field reduction while maintaining compact overall dimensions.
2Volume of moving object
If the distances between the coils of the pair of coils included in each of the power transmitter coil and the power receiver coil are configured to be shorter than the distance between the power transmitter coil and the power receiver coil, then the physical sizes of the power transmitter coil and the power receiver coil are avoided to be increased, but the oppositely oriented magnetic fluxes generated by the pair of coils will interfere with each other and cause the interlinkage magnetic fluxes that are interlinked with the power receiver coil to be reduced, thereby reducing the coupling coefficient between the power transmitter coil and the power receiver coil and eventually reducing the power transmission efficiency
Solution Approach 1:
The asymmetric spacing configuration ensures that while the coils are close enough to maintain compact size, the specific arrangement with longer inter-coil distance within the pair prevents complete cancellation of useful magnetic flux. This asymmetric design allows differentiation between harmful leakage flux (reduced) and useful interlinkage flux (maintained).
Solution Approach 2:
The patent applies local quality by having different spacing characteristics in different parts of the coil structure: the pair of coils has longer spacing between them, while the distance to the opposing coil is shorter. This local variation in spacing creates different magnetic field conditions in different regions, allowing simultaneous reduction of leakage field and maintenance of coupling efficiency.
3Object-generated harmful factors
If the distances between the coils of the pair of coils included in each of the power transmitter coil and the power receiver coil are configured to be longer than the distance between the power transmitter coil and the power receiver coil, then the leakage magnetic field is reduced, but the device complexity is increased due to the specific distance configuration requirements
Solution Approach 1:
The asymmetric distance configuration provides a clear design rule that simplifies implementation: simply make the distance between the pair of coils longer than the distance to the opposing coil. This single asymmetric parameter specification is easier to implement than complex symmetric arrangements with multiple constrained dimensions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces leakage magnetic fields and maintains power transmission efficiency by balancing magnetic fields and coil sizes, enhancing coupling coefficients.
Implementation Method 1
a wireless power transfer system that wirelessly transfers power from a power transmitter coil to a power receiver coil
Implementation Method 2
a power transmitter coil includes a first unit coil and a second unit coil arranged spaced apart from each other on a first face in a first direction, each coil being configured in such a way that currents flowing through them are in opposite phases
Data Source
AI summary
A wireless power transfer system is configured in such a way that: the power transmitter coil and the power receiver coil each include a coil unit, the coil unit being a pair of coils arranged side by side in a horizontal direction; each of the coils in the coil unit has a shape formed by being wound in a horizontal plane and those coils are configured in such a way that magnetic fields generated by currents are oriented oppositely to each other; a connecting portion is provided on outside diameter sides of adjacent longer sides of the pair of coils, the longer sides being opposed to each other; and the coils are wound to be substantially point-symmetric about a substantially central point of the connecting portion as a point of symmetry in such a way that coil widths of all longer sides of the pair of coils are substantially equal.